Induction dynamo-electric machine



March '18 1924.

1,487,286 w. TAYLOR mnuc'rxou 'DYNAMO ELEc'rRic MACHINE Filed Feb. 15,v192: 3 Sheets-Sheet 1 F g. I

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l'rm/entcn- 1 Henry W. Taylor",

His Attorney.

March 18 1924. 1,487,286

H. w. TAYLOR INDUCTION DYNKMO ELECTRIC MACHINE Filed Feb- 15. 1922 sSheets-Sheet 2 Inventor I Henry W. Taylor,

' by Mam HI'S Attorney.

March 18, 1924. 1,487,286

H. W. TAYLOR INDUCTION DYNAMO ELECTRIC MACHINE Filed Feb- 15, 1922 5Sheets-Sheet 5 Fig.8.

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[rm/enter? I H enr-y W Taylor,

His Attorney.

Patented Mar. 18, 1924.

umreo STATES PATENT OFFICE.

HENRY W. TAYLOR, OF RUGBY, ENGLAND, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

INDUCTION DYNAMO-ELECTRIC MACHINE.

Application filed February 15, 1922. Serial No. 536,774.

To all whom it may concern:

Be it known that I, HENRY WILLIAM TAY- LOR, a subject of the King ofGreat Britain,

residing at Rugby, in the county of VVar- 5 wick, England, have inventedcertain new and useful Improvements in Induction Dynamo-ElectricMachines, of which the following a specification.

My invention relates to improvements in 1 the secondary windings ofdynamo electric machines of the induction type. 'In such windings, it isdesirable that the conductors have a high resistance when carryingcurrent at the line frequency and a low resist- 1 ance when carryingcurrent at a slip frequency. In order to accomplish this, deepconductors in parallel sided slots have been used, but in many cases thedepth of the conductors to produce the necessary multiplication of theresistance at the higher frequency is so great as to render such aconstruction impractical.

In addition composite conductors have been proposed consisting of an uper and lower section, the upper section usua ly having a much higherresistance than the lower section, the two sections being placed a shortdistance from one another in the slot and the intervening space beingnearly filled with magnetic material. TlllS construction, however, alsohas in practice limitations.

The object of my'invention is to provide improvements in theconstruction of such composite conductors, and these consist essentlallyof using a number of such composite conductors in the depth of the slotand arranging that each unit conductor carries the same amount ofcurrent. In this way the currents which flow in the lower units produceextra circulating currents in the sections of the upper units and thusgives an increased resistance effect at hi h frequencies. I may arrangeto connect t e composite conductors or the sections of the compositeconductors in a number of ways outside the core, as for instance thesections of the composite conductors may be joined to gether immediatelyafter leaving the core, or at the end of each half turn so that thecurrent induced in the sections of the upper composite conductors by thecurrents in the lower conductors passes only over the conductor in whichit is generated.

Alternately I may arrange for the sections of some or all of thecomposite conductors to be continuously electrically insulated and I mayarrange the order of the sections, as they traverse th various positionsoccupied by the conductor so that the voltage induced between thembecomes cumulative.

The features of my invention which I believe to be novel and patentablewill be pointed out in the claims appended hereto. The accompanyingdiagrams illustrate my invention, Fig. 1 indicating a form of compositeconductor which has been used in previous constructions. Fig. 2 shows animproved arrangement consisting of two composite conductors in the sameslot, and Figs. 3, 4 and 5 show different methods in which the ends ofthe sections of the composite conductors illustrated in Fig. 2 may beconnected when they are made to form complete coils. Fig. 6 shows afurther development of my invention in which four separate compositeconductors are arranged in the same slot and Fig. 7 shows a method ofmaking the end connections of the sections of the composite conductorsillustrated in Fig. 6 so that the voltage induced between the sectionsmay be cumulative.

Figs. 8 and 9 show how composite conductors used in accordance with myinvention may be connected to form the well-known squirrel cage form ofwindings.

Fig. 1 shows a simple composite conductor in a slot, at and 6 indicatingthe sections of the conductor and c the space between the sections whichis partly occupied by magnetic material.

Although in the following description, I have described my inventionwith reference to the form of winding shown in Fig. 1, I do not limitmyself to this form.

Fig. 2 illustrates a form of my invention in which I use two separatecomposite conductors in the same slot; a and 6 represents two sectionswhich are associated with one another to form one conductor with theintervening slot space narrowed as at d and below them, a and b are twofurther sections which form a second composite conductor electricallyinsulated as far as a single slot is concerned, from sections a and a.In order that each of the two separate composite conductors may carrythe same current I may form a succession of shortcircuited coils asshown in Figs. 3, at and 5 by choosing slots preferably a pole pitchapart, and by taking the upper composite conductor on one pole andconnecting it to the lower conductor in the next pole. In this way anupper composite conductor is always subjected to the magnetizinginfluence of a lower composite conductor and has generated in it acirculating current which in effect produces an increase in theequivalent resistance of the coil at higher frequencies. In Fig. 3 Ihave shown the section of the composite conductors joined solidlytogether at the ends of the slots, but in. some cases it may beadvantageous toextend the electrical separation and to only join thesections together at the end of the half turns as shown in Fig. 4:

In Fig. 5 I have shown an arrangement in which there is no electricalconnection between sections of the composite conductors throughout theturn and in this case it will be noticed that in order to produce thebest effect I have connected the upper section a of the upper compositeconductor to the upper section a of the lower composite conductor andthe lower section b of the upper conductor to the lower section b of thelower conductor.

Referring now to Fig. 6, I have shown a form of my invention whichconsists of four composite conductors each consisting of two sectionsand all arranged in the same slot, all sections and conductors beingelectrically insulated from one another. It will be understood that inaccordance with the principle of my invention as described above, thefour conductors will be so connected that each conductor carries thesame current and that the sections of the conductor may be connected inany of the manners previously shown in Figs. 3, 4 and 5. In Fig. 7 Ihave shown diagrannnatically how the sections of the conductors may beconnected in a manner corresponding to Fig. 5. so that there is nointerconnection between the sections and all the upper sections, a, a a,and a are connected together in sequence and all the lower sections 1),b, b, and 5 are also connected together in sequence, so that the voltagegenerated in the sections ofthe upper conductors by the currents in thelower ones will become cumulativeto a maximum degree.

Coming now to formsof my invention in which the composite conductors areconnected to a common bar at theends of the slots in Fig. 8 I have shownan arrangement which is suitable for use when two composite conductorsare arranged in the same slot to ensure that each conductor carries thesame value of current. At each end of the wind ing I provide two shortcircuiting rings S, S and having divided the total slots around thewinding into sections corresponding to the number of poles, I connectfor instance the top composite conductor on one pole to one set of shortcircuiting rings S and on the other pole I connect the bottom compositeconductor 0, 5 to the same rings S and the top composite conductor a, Z)to the other rings S.

Further Fig. 9 shows the further development in which I use fourcomposite conductors in each slot as shown in Fig. 6 and four shortcircuiting rings at each end of the rotor. It will be observed that Iconnect the different composite conductors to the different shortcircuiting rings on the adjacent poles so that current circulatesthrough all four conductors before completing the circuit, I therebyensure that the same current will flow in each conductor.

I donot wish to confine myself to the use of composite conductorsconsisting of two sections only as above described. nor do I wish tolimit myself to the use of composite conductors having sections all ofthe same resistance. Also I do not wish to limit myself to the use ofsets of composite conductors in the same slot having all the same characteristics as regards size of sections and inter magnetizable spaces, butwhere necessary I may vary all these features in order to produce anyrequired variation in the equivalent resistance of the conductor atdifferent frequencies.

WVhat I claim as new and desire to secure by Letters Patent of theUnited States, is

1. The secondary of a dynamo electric machine of the induction typecomprising a slotted magnetic structure, a plurality of compositeconductors at different depths in the slots, each composite conductorconsisting of a plurality of sections, said sections being separatedfrom each other by a magnetizable medium and end connections for causingthe conductors to carry the same value of current.

2. The secondary member of a dynamo electric machine of the inductiontype comprising a slotted magnetic structure and a plurality ofsectional conductors at different depths in said slots, said conductorsections being insulated from each other and separated by a magnetizablemedium and end connections for connecting sections of differentconductors in closed windings in such a manner as to cause all of saidconductors to carry the. same value of current.

. 3. A winding for a dynamo electric ma: chine of the type in which theequivalent resistance of the winding increase with the frequency, havingtwo or more composite conductors in a slot, each composite conclosedcoils, the sections being insulated from 10 ductor consisting of two ormore sections one another throughout the coil. separated from each otherby amagnetlzable In witness whereof, I have hereunto set medium togetherwith connections at the my hand this 25th day of January, 1922. ends ofthe winding so that each composite conductor carries the same current.H. W. TAYLOR.

4. A winding as claimed in claim 1, charac- Witnesses: terized by thefact that the sections of the J. A. Fos'mn,

conductors are connected together to form D. WHITI.

